Implantable System for Long- and Short-Term Active Charge Balancing in Neural Electrical Stimulation

功能性电刺激是一种允许通过电荷刺激神经的技术。为了避免电荷积累导致组织损伤和电极腐蚀，特别是在长期治疗过程中，电荷平衡已成为功能电刺激的一个组成部分。然而，出于可靠性原因，大多数ce认证的医疗设备都配备了被动电荷平衡系统，尽管它们体积大，稳定时间长，并且不受控制的电荷补偿。有源电荷平衡是一种小、快、可控的电荷补偿方法。当测量和刺激同时进行时，该技术还具有更好的信号质量的优点。本项目将对采用有源电荷平衡的电刺激进行基础研究，以降低刺激风险，节省慢性试验。目的是开发和评估一种CMOS集成、高压兼容的电荷平衡系统，该系统可以与各种刺激器结合使用。除了对可植入系统的典型要求，例如低功耗和低面积需求，常见应用的多样性要求主动电荷平衡系统具有高适应性和灵活性，例如可配置的安全限值，输出电流限制和具有高达30V的高压兼容性的自适应供电轨道。为了满足这些要求并实现明确的电荷平衡，将考虑和追求长期和短期刺激的主动电荷平衡的互补方法，无论是单独的还是组合的。每种方法都代表了一个执行良好的控制回路，同时提供了在相互结合时实现更好的电荷平衡性能的机会。考虑到多电极配置和多输入多输出系统，将考虑和开发链接控制回路的方法，并评估其稳定性，相互作用和性能。

Functional electrical stimulation is a technique that allows for the stimulation of nerves by electrical charge. In order to avoid charge accumulation which causes tissue lesion and electrode corrosion, in particular during long-term treatments, charge balancing has become an integral part of functional electrical stimulation. However, for reliability reasons, most CE-certified medical devices are equipped with passive charge balancing systems today, despite their large size, long settling time, and uncontrolled charge compensation. A promising approach to small, fast, and well controlled charge compensation is active charge balancing. This technique also comes up with the advantage of a better signal quality when measurements and stimulations are performed simultaneously. In this project, fundamental research will be performed on electrical stimulation using active charge balancing in order to reduce the risks of stimulation and facilitate save chronic trials. The objective is to develop and evaluate a CMOS integrated, high-voltage compatible charge balancing system, which can be used in combination with a variety of stimulators. In addition to the typical requirements on implantable systems, e.g., low-power consumption and low-area demand, the diversity of common applications necessitates a high adaptability and flexibility of the active charge balancing system in terms of, e.g., configurable safety limits, output current limitation and adaptive supply rails with high-voltage compatibility up to 30V.In order to meet these requirements and to achieve a well-defined charge balancing, the complementary approaches to active charge balancing for long- and short-term stimulation will be considered and pursued, both separately and in combination. Each approach represents a sufficiently well performing control loop while providing the opportunity to achieve a better performance in charge balancing when being combined with each other. Considering multiple-electrode configurations and thus multiple-input multiple-output systems, approaches to linked control loops will be considered and developed and their stability, interaction, and performance evaluated.